Multiple windows turn black on minimizing a window after switching variant type in Rule information. Refer the attached video

Steps to reproduce:
1) Create a new project
2) Window > Package Manager > Install Remote Config
3) Create Environment > Add rule
4) Dock Remote Config Window > Maximize window
5) Change variant > Minimize window

Actual result: Multiple windows turn black on minimizing Remote Config window

Expected result: Windows should not turn black on minimizing Remote Config window

Occurring on: 2020.2.0a17 and 2020.1.0b16 with Remote Config package version 1.2.3, 1.2.2, 1.2.1

Note: Variant type in Remote Config window was introduced in 1.2.1

Environment: Seen on Windows and Mac

Stack trace:

OnGUIDepth changed: was 2 is 3. Event type was 7
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Unity.RemoteConfig.Editor.RemoteConfigWindow:OnDestroy () (at Library/PackageCache/com.unity.remote-config@1.2.1/Editor/RemoteConfigWindow.cs:457)
UnityEditor.GenericMenu:CatchMenu (object,string[],int)

OnGUIDepth changed: was 3 is 4. Event type was 7
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Unity.RemoteConfig.Editor.RemoteConfigWindow:OnDestroy () (at Library/PackageCache/com.unity.remote-config@1.2.1/Editor/RemoteConfigWindow.cs:457)
UnityEditor.GenericMenu:CatchMenu (object,string[],int)